Stephen W. Link

Modeling imageless thought: The relative judgment theory of numerical comparisons ☆

Abstract The mental process of comparing numbers is shown to follow the principles of Relative Judgment Theory. Martingale predictions of the theory are confirmed in an extensive study of numerical comparisons using the Method of Symmetric Differences. The theory is then used as a tool to reveal the Psychonumeric Function relating psychological difference to numerical difference. This function transforms a difference between numbers into a sextal valued (0, 1, 2, 3, 4, 5) number with zero as a unit psychonumeric value. The Psychonumeric Function combined with the theorys prediction of response times gives a close account of the numerical comparison Chronometric Function.

A theory of cheating

The theory of motivated cheating postulates that test takers may cheat when they do not know an answer. With probabilityk, an “observer” is unsure of an answer and will copy from a nearby “target” with probabilityc. The corresponding parameters for the target may be entirely unrelated to those of the observer. Thus, the undesirable feature of bidirectionality of parameters found in correlational techniques is not an inherent feature of this theory of cheating. Predictions are derived, and estimates ofk andc are proposed. Statistically large values of c suggest that an observer was copying from a target. High values ofc for both the observer and the target suggest collusion. The theory is applied to a 40-item five-choice test taken by students in an introductory psychology section. From the full paired comparison matrix of target × observer parameter estimates, the method identifies 2 students who were probably in collusion.

Commentary on high-performance computing and human vision II: Virtual reality and eyeball tracking

Visualization of scientific data that are not normally visible can be greatly enhanced by understanding human visual perception. Mars the Movie illustrated the use of stereo resolution for producing realistic vistas of the Mars surface. The real-time recording and analysis of eyeball-tracking data is another example of human vision research which benefits from high-performance computing. Currently the bottleneck is not in the hardware but in the available software to transform data efficiently.

High-performance computer applications in the behavioral sciences

This symposium revisited the 1985 conference on Advanced Computing for Psychology. That meeting examined the application of new supercomputers in the behavioral sciences. The present symposium reviewed high-performance computing as applied to psychological models, human vision, neuralphysiological processes, and statistical analysis. The recent past and the projected future of high-performance computing in the behavioral sciences were evaluated.

Commentary on high-performance computing and psychological models: Theory-building and model-fitting processes

For a psychological theorist, a merging of the interactive capability of a desktop computer and the speed/ memory capability of a supercomputer is needed. Ready-to-use modeling software is especially useful in the behavioral sciences so that researchers do not need to reinvent each other’s wheels. Dynamical models of psychological processes require different analyses from routine statistical treatments.